US9483979B2 - Pixel circuit, driving method thereof, and display device - Google Patents

Pixel circuit, driving method thereof, and display device Download PDF

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US9483979B2
US9483979B2 US14/132,614 US201314132614A US9483979B2 US 9483979 B2 US9483979 B2 US 9483979B2 US 201314132614 A US201314132614 A US 201314132614A US 9483979 B2 US9483979 B2 US 9483979B2
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tft
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drain
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US20140175992A1 (en
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Shengji Yang
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Beijing BOE Optoelectronics Technology Co Ltd
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Beijing BOE Optoelectronics Technology Co Ltd
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    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • G09G3/3208Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
    • G09G3/3225Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
    • G09G3/3233Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the current through the light-emitting element
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00Aspects of the constitution of display devices
    • G09G2300/08Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809Several active elements per pixel in active matrix panels
    • G09G2300/0819Several active elements per pixel in active matrix panels used for counteracting undesired variations, e.g. feedback or autozeroing
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00Aspects of the constitution of display devices
    • G09G2300/08Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809Several active elements per pixel in active matrix panels
    • G09G2300/0842Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor
    • G09G2300/0861Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00Command of the display device
    • G09G2310/02Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0243Details of the generation of driving signals
    • G09G2310/0251Precharge or discharge of pixel before applying new pixel voltage
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00Command of the display device
    • G09G2310/02Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0262The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes

Abstract

Provided are a pixel circuit, a driving method thereof, and a display device, which relate to the field of the display technology and can effectively compensate variation in currents due to ununiformity and drift of threshold voltages of driving Thin Film Transistors as well as ununiformity of OLEDs. The pixel circuit comprises: a light-emitting element; a driving TFT; a first TFT having a drain connected to a gate of the driving TFT; a second TFT having a drain connected to a source of the driving TFT; a third TFT having a source connected to a drain of the driving TFT, and a drain connected to the light-emitting element; a fourth TFT having a source connected to the gate of the driving TFT, and a drain connected to the drain of the driving TFT; a fifth TFT having a drain connected to the source of the driving TFT; and a capacitor.

Description

TECHNICAL FIELD

The present disclosure relates to a field of display technology, in particular to a pixel circuit, a driving method thereof, and a display device.

BACKGROUND

An Organic Light Emitting Diode (OLED) is a current-driven self-luminous type device, and for its unique characteristics such as self-illumination, fast response, wide viewing angle and the capability of being manufactured on a flexible substrate, an organic light-emitting display device based on the OLED is expected to become the mainstream in the field of display technology in the next years.

Each of display units on an organic light-emitting display device comprises an OLED, and the organic light-emitting display device can be divided into an active organic light-emitting display device and a passive organic light-emitting display device, wherein the active organic light-emitting display device refers to a display device in which, for each OLED, the current flowing through the OLED is controlled by a Thin Film Transistor (TFT) circuit, and the OLED and the TFT circuit for controlling the OLED constitute a pixel circuit.

A typical pixel circuit is illustrated in FIG. 1 and the pixel circuit comprises 2 TFTs, 1 capacitor and 1 OLED, wherein a switch transistor T2 transmits a data voltage on a data line to a gate of a driving transistor T1, and the driving transistor T1 converts the data voltage to a corresponding current for supplying to the OLED, wherein the current can be represented as follows:

I OLED = 1 2 μ n · Cox · W L · ( Vgs - Vth ) 2 = 1 2 μ n · Cox · W L · ( Vdata - Voled - Vth ) 2 ( 1 )

wherein Vgs represents a potential difference between the gate and a source of the driving transistor T1, μn represents a carrier mobility, Cox represents a capacitance of gate-insulating layer, W/L represents a ratio of width to length of channel of the driving transistor T1, Vdata represents the data voltage, Voled represents an operating voltage of the OLED, and Vth represents a threshold voltage of the driving transistor T1. It can seen from the above equation that there is variation in currents flowing through the OLEDs if Vth varies in different pixel units or Vth drifts with time, thus affecting the display effect; further, the OLEDs have different operating voltages due to the ununiformity of OLEDs, which in turn results in variation in currents flowing through the OLEDs.

SUMMARY

In embodiments of the present disclosure, there is provided a pixel circuit, a driving method thereof, and a display device, which can effectively compensate variation in currents due to the ununiformity and drifts in the threshold voltages of the driving Thin Film Transistors as well as the ununiformity of OLEDs, thus enhancing display quality of the display device.

According to one aspect of the present disclosure, there is provided a pixel circuit comprising:

a light-emitting element;

a driving Thin Film Transistor (TFT) for driving the light-emitting element;

a first TFT having a source connected to a reference voltage terminal, a drain connected to a gate of the driving TFT, and a gate for receiving a first control signal;

a second TFT having a gate for receiving a first scan signal, a drain connected to a source of the driving TFT, and a source for receiving a data voltage signal;

a third TFT having a gate for receiving a second scan signal, a source connected to a drain of the driving TFT, and a drain connected to the light-emitting element;

a fourth TFT having a gate for receiving the first scan signal, a source connected to the gate of the driving TFT, and a drain connected to the drain of the driving TFT;

a fifth TFT having a gate for receiving the second scan signal, a source connected to a power supply voltage terminal, and a drain connected to the source of the driving TFT;

a capacitor having one terminal connected to a first node A, and the other terminal connected to a second node B, wherein the first node A is a connection point where the drain of the first TFT and the gate of the driving TFT are connected, and the second node B is connected to the reference voltage terminal.

Optionally, the first, second, third, fourth, and fifth TFTs and the driving transistor are all P type Thin Film Transistors.

Optionally, the light-emitting element is an Organic Light-Emitting Diode.

According to another aspect of the present disclosure, there is further provided a display device having any of the pixel circuits described as above arranged therein.

According to still another aspect of the present disclosure, there is further provided a driving method applicable to the pixel circuit as above comprising:

in a resetting phase, turning on the first TFT under a control of a first control signal, discharging electric charges stored at the first node A via the first TFT, resetting a voltage signal at the gate of the driving TFT so as turn on the driving TFT, and turning off the second TFT, the third TFT, the fourth TFT and the fifth TFT;

in a compensating phase, turning on the second TFT and the fourth TFT under a control of a first scan signal, making the driving TFT continue to be turned on, wherein since the fourth TFT is turned on, the gate and the drain of the driving TFT are connected electrically; charging the first node A by a data signal via the driving TFT, so that a voltage at the node A rises; and turning off the first TFT, the third TFT and the fifth TFT; and

in a maintaining light-emission phase, turning on the third TFT and the fifth TFT under a control of the second scan signal, keeping the voltage at the gate of the driving TFT unchanged by the capacitor, and making the driving TFT continue to be turned on, and driving the OLED to emit light by a power supply voltage; and turning off the first TFT, the second TFT and the fourth TFT.

In the pixel circuit, the driving method thereof and the display device provided in the embodiments of the present disclosure, one terminal of the capacitor is connected to the gate of the driving TFT (the first node), and the other terminal of the capacitor is connected to the reference voltage terminal; the fifth TFT is controlled so that the source of the driving TFT receives the power supply voltage, and the third TFT is controlled so that the drain of the driving TFT is connected to the light-emitting element. The process for displaying each frame of image includes three phases, i.e., the resetting phase, the compensating phase, and the maintaining light-emission phase. In the resetting phase, the first TFT is turned on, the electric charges stored at the first node is discharged, so that the voltage at the first node is pulled down and thus the driving TFT is turned on; in the compensating phase, the second and fourth TFTs are turned on, and the gate and the source or drain of the driving TFT are connected electrically, so that the voltage at the first node contains information on the threshold voltage of the driving TFT; in the maintaining light-emission phase, the third and fifth TFTs are turned on, the voltage at the gate of the driving TFT remains unchanged, and the power supply signal drives the light-emitting element to emit light, wherein the current through the light-emitting element is independent of the threshold voltage of the driving TFT and the voltage across the light-emitting element. Thus, variation in currents due to the ununiformity and drift of the threshold voltages of the driving TFTs as well as the ununiformity of OLEDs can be compensated effectively, thus enhancing the display quality of the display device; at the same time, TFTs of the same type are adopted in the pixel circuit so as to not only ensure that no current flows through the OLED during all the non-light-emission periods, but also improve a life span of the OLED.

BRIEF DESCRIPTION OF THE DRAWINGS

In following description, the features and advantages of the embodiments of the present disclosure will be more apparent in connection with the accompanying drawings. In the whole drawings, the same content is denoted with the same reference number, wherein,

FIG. 1 is a schematic diagram showing a structure of a pixel circuit in the prior art;

FIG. 2 is a schematic diagram showing a pixel circuit provided in an embodiment of the present disclosure;

FIG. 3 is a timing control diagram of the pixel circuit in an embodiment of the present disclosure;

FIG. 4 is a flowchart of a driving method of the pixel circuit in an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

In embodiments of the present disclosure, there is provided a pixel circuit, a driving method thereof, and a display device, which can effectively compensate variation in currents due to the ununiformity and drift of the threshold voltages of driving Thin Film Transistors as well as the ununiformity in OLEDs, thus enhancing the display quality of the display device; at the same time, TFTs of a same type are adopted in the pixel circuit so as to not only ensure that no current flows through the OLED during all the non-light-emission periods, but also improve the life span of the OLED.

Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The specific embodiments as described herein are only for illustrating some aspects of the present disclosure, and are not intended to limit the protection scope of the present disclosure in any way.

It should be noted that there is no clear distinction between a drain and a source of a transistor used in the field of Liquid Crystal Display technology, and thus a source of a transistor described in the embodiments of the present disclosure can serve as a drain of the transistor, and a drain of a transistor described in the embodiments of the present disclosure can serve as a source of the transistor.

A pixel circuit provided in an embodiment of the present disclosure is as shown in FIG. 2 and comprises:

a light-emitting element 207;

a driving Thin Film Transistor (TFT) 200 for driving the light-emitting element 207;

a first TFT 201 having a source connected to a reference voltage terminal, a drain connected to a gate of the driving TFT 200, and a gate for receiving a first control signal EM;

a second TFT 202 having a gate for receiving a first scan signal Vscan1, a drain connected to a source of the driving TFT 200, and a source for receiving a data voltage signal Vdata;

a third TFT 203 having a gate for receiving a second scan signal Vscan2, a source connected to a drain of the driving TFT 200, and a drain connected to the light-emitting element;

a fourth TFT 204 having a source connected to the gate of the driving TFT 200, a drain connected to the drain of the driving TFT 200, and a gate for receiving the first scan signal Vscan1;

a fifth TFT 205 having a gate for receiving the second scan signal Vscan2, a source connected to a power supply voltage terminal for receiving a power supply voltage Vdd, and a drain connected to the source of the driving TFT 200;

a capacitor 206 having one terminal connected to a first node A, and the other terminal connected to a second node B, wherein the first node A is a connection point where the drain of the first TFT 201 and the gate of the driving TFT 200 are connected, and the second node B is connected to the reference voltage terminal.

The above pixel circuit comprises 5 TFTs and 1 capacitor, wherein the 5 TFTs (T1˜T5) are all P type TFTs for facilitating manufacture. Preferably, except the driving TFT, all TFTs adopt P type TFTs having a same structure and a same size. Optionally, the light-emitting element 207 is an Organic Light-Emitting Diode (OLED).

The pixel circuit provided in the embodiment of the present disclosure can effectively compensate variation in currents due to the ununiformity and drift of the threshold voltages of the driving TFTs as well as the ununiformity of OLEDs (the details of the operational principle are as follows), thus enhancing the display quality of the display device; at the same time, TFTs of the same type are adopted in the pixel circuit so as to not only ensure that no current flows through the OLED during all the non-light-emission periods, but also improve the life span of the OLED.

Transistors employed in the pixel circuit shown in FIG. 2 are all P type TFTs, and a timing control of the pixel circuit is illustrated schematically in FIG. 3, wherein the process for displaying each frame of image includes three phases of resetting (I), compensating (II) and maintaining light-emission (III), and as shown in FIG. 3, particularly comprises the following steps or phases.

In step 101, i.e., in a resetting phase (I), a first scan signal Vscan1 and a second scan signal Vscan2 are at a high level, and a first control signal EM is at a low level, so that the first TFT 201 is turned on under a control of the first control signal EM, electric charges stored at the first node A are discharged via the first TFT 201, a voltage signal at the gate of the driving TFT 200 is reset and the driving TFT 200 is turned on, and the second TFT 202, the third TFT 203, the fourth TFT 204 and the fifth TFT 205 are turned off under the control of the first scan signal Vscan1 and the second scan signal Vscan2.

In summary, in the resetting phase (I), among the five P type TFTs, except that the first TFT 201 is turned on, other TFTs in five P type TFTs, i.e., TFTs 202-205 are turned off, the electric charges stored at the first node A are discharged via the first TFT 201, the voltage signal at the gate of the driving TFT 200 is reset and the driving TFT 200 is turned on.

In step 102, i.e., in a compensating phase(II), the first scan signal Vscan1 is at a low level, the second scan signal Vscan2 is at a high level, and the first control signal EM is at a high level, so that the second TFT 202 and the fourth TFT 204 are turned on under a control of the first scan signal Vscan1, the driving TFT 200 continues to be turned on; since the fourth TFT 204 is turned on, the gate and the drain of the driving TFT 200 are connected electrically, the first node A is charged by a data signal Vdata via the driving TFT 200, so that the voltage at the node A rises; the first TFT 201, the third TFT 203 and the fifth TFT 205 are turned off under the control of the second scan signal Vscan 2 and the first control signal EM.

In summary, in the compensating phase (II), the second TFT 202 and the fourth TFT 204 are turned on, the first TFT 201, the third TFT 203 and the fifth TFT 205 are turned off, and the driving TFT 200 continues to be turned on; since the fourth TFT 204 is turned on, the gate and the drain of the driving TFT 200 are connected electrically, the first node A is charged by the data signal Vdata via the driving TFT 200, so that the voltage at the node A rises until the voltage at the node A is equal to Vdata−Vth. At the end of the compensating phase (II), the quantity of the electric charges Q on the capacitor 206 is equal to:
Q=C (V 2 −V 1)=C·(V REF +V th −V data)  (2)

wherein, V1 represents the voltage at the first node A at this time, and is equal to Vdata−Vth; V2 represents the voltage at the second node B at this time, and is equal to the voltage VREF at the reference voltage terminal; in the embodiments of the present disclosure, the reference voltage terminal is grounded, and the voltage VREF is equal to 0.

In step 103, i.e., in a maintaining light-emission phase (III), the first scan signal Vscan1 is at a high level, the second scan signal Vscan2 is at a low level, and the first control signal EM is at a high level, so that the third TFT 203 and the fifth TFT 205 are turned on under a control of the second scan signal Vscan2; the capacitor 206 keeps the voltage at the gate of the driving TFT 200 unchanged, and the driving TFT 200 continues to be turned on, and the OLED is driven to emit light by a power supply voltage Vdd; the first TFT 201, the second TFT 202 and the fourth TFT 204 are turned off under the control of the first scan signal Vscan 1 and the first control signal EM.

In summary, in the maintaining light-emission phase, the third TFT 203 and the fifth TFT 205 are turned on, the first TFT 201, the second TFT 202 and the fourth TFT 204 are turned off; the capacitor 206 keeps the voltage at the gate of the driving TFT 200 still equal to Vdata−Vth, and the voltage at the source of the driving TFT 200 is equal to the power supply voltage Vdd; in order to ensure that the driving TFT 200 is turned on during the maintaining light-emission phase, the power supply voltage Vdd is designed to be less than the data signal voltage Vdata, and the OLED is driven to emit light by the power supply voltage Vdd.
V gs =V s −V g =V dd +V th −V data  (3)

The gate-source voltage of the driving TFT 200 remains at Vdd+Vth−Vdata, and at this time the current through the driving TFT 200 is as follows:

I OLED = 1 2 · μ n · Cox · W L · [ V dd - V data + V th - V th ] 2 = 1 2 · μ n · Cox · W L · [ V dd - V data ] 2 ( 4 )

It can be known from the above equation that the current through the driving TFT 200 has a relation to the power supply voltage Vdd and the data voltage Vdata, and is independent of the threshold voltage Vth. Thus, the effects of the ununiformity and drift of the threshold voltages of the driving TFTs as well as the ununiformity of the electrical characteristics of the OLEDs can be eliminated.

According to the embodiments of the present disclosure, there is further provided a display device having any of the pixel circuits described as above arranged therein. Since the pixel circuit can effectively compensate variation in currents due to the ununiformity and drift of the threshold voltages of the driving TFTs as well as the ununiformity of OLEDs, the display device provide in the embodiment of the present disclosure have advantages such as uniform brightness and better display quality.

The display device can be an OLED panel, a mobile phone, a tablet computer, a television set, a display, a notebook computer, a digital photo frame, a navigator, and any product or means having a display function.

The technical features in the embodiments of the present disclosure can be combined with each other in any way in a case where there is no confliction therebetween.

The above descriptions are only for illustrating the embodiments of the present disclosure, and in no way limit the scope of the present disclosure. It will be obvious that those skilled in the art may make modifications, variations and equivalences to the above embodiments without departing from the spirit and scope of the present disclosure as defined by the following claims. Such variations and modifications are intended to be included within the spirit and scope of the present disclosure.

Claims (10)

What is claimed is:
1. A pixel circuit comprising:
a light-emitting element;
a driving Thin Film Transistor (TFT) for driving the light-emitting element;
a first TFT having a source connected to a reference voltage terminal, a drain connected to a gate of the driving TFT, and a gate for receiving a first control signal;
a second TFT having a gate for receiving a first scan signal, a drain connected to a source of the driving TFT, and a source for receiving a data voltage signal;
a third TFT having a gate for receiving a second scan signal, a source connected to a drain of the driving TFT, and a drain connected to the light-emitting element;
a fourth TFT having a gate for receiving the first scan signal, a source connected to the gate of the driving TFT, and a drain connected to a first electrode of the driving TFT, wherein the first electrode of the driving TFT is drain or the source of the driving TFT;
a fifth TFT having a gate for receiving the second scan signal, a source connected to a power supply voltage terminal, and a drain connected to the source of the driving TFT;
a capacitor having one terminal connected to a first node A, and the other terminal connected to a second node B, wherein the first node A is a connection point where the drain of the first TFT is connected to the gate of the driving TFT, and the second node B is connected to the reference voltage terminal;
wherein the reference voltage terminal keeps its voltage unchanged.
2. The pixel circuit of claim 1, wherein the first TFT, the second TFT, the third TFT, the fourth TFT, and the fifth TFT and the driving TFT are all P type thin Film Transistors, and the first electrode of the driving TFT is the drain of the driving TFT.
3. The pixel circuit of claim 2, wherein the power supply voltage terminal supplies a positive power supply voltage, the positive power supply voltage is higher than a reference voltage at the reference voltage terminal, and a data voltage of the data voltage signal is lower than the positive power supply voltage.
4. The pixel circuit of claim 2, wherein an anode of the light-emitting element is connected to the drain of the third TFT, and a cathode of the light-emitting element is connected to the reference voltage terminal.
5. A display device having the pixel circuit of claim 1 arranged therein.
6. The display device of claim 5, wherein the first TFT, the second TFT, the third TFT, the fourth TFT, and the fifth TFT and the driving TFT are all P type Thin Film Transistors, and the first electrode of the driving TFT is the drain of the driving TFT;
the power supply voltage terminal supplies a positive power supply voltage, the positive power supply voltage is higher than a reference voltage at the reference voltage terminal, and a data voltage of the data voltage signal is lower than the positive power supply voltage.
7. The display device of claim 6, wherein, in the pixel unit, an anode of the light-emitting element is connected to the drain of the third TFT, and a cathode of the light-emitting element is connected to the reference voltage terminal.
8. A method for driving a pixel circuit, the pixel circuit comprising:
a light-emitting element;
a driving Thin Film Transistor TFT for driving the light-emitting element;
a first TFT having a source connected to a reference voltage terminal, a drain connected to a gate of the driving TFT, and a gate for receiving a first control signal;
a second TFT having a gate for receiving a first scan signal, a drain connected to a source of the driving TFT, and a source for receiving a data voltage signal;
a third TFT having a gate for receiving a second scan signal, a source connected to a drain of the driving TFT, and a drain connected to the light-emitting element;
a fourth TFT having a gate for receiving the first scan signal, a source connected to the gate of the driving TFT, and a drain connected to a first electrode of the driving TFT, wherein the first electrode of the driving TFT is the drain or the source of the driving TFT;
a fifth TFT having a gate for receiving the second scan signal, a source connected to a power supply voltage terminal, and a drain connected to the source of the driving TFT;
a capacitor having one terminal connected to a first node A, and the other terminal connected to a second node B, wherein the first node A is a connection point where the drain of the first TFT is connected to the gate of the driving TFT, and the second node B is connected to the reference voltage terminal,
the method comprising:
in a resetting phase, turning on the first TFT under a control of a first control signal, discharging electric charges stored at the first node via the first TFT, resetting a voltage signal at the gate of the driving TFT so as turn on the driving TFT, and turning off the second TFT, the third TFT, the fourth TFT and the fifth TFT;
in a compensating phase, turning on the second TFT and the fourth TFT under a control of a first scan signal, making the driving TFT continue to be turned on, wherein since the fourth TFT is turned on, the gate and the drain of the driving TFT are connected electrically; charging the first node by a data signal via the driving TFT, so that a voltage at the node rises; and turning off the first TFT, the third TFT and the fifth TFT; and
in a maintaining light-emission phase, turning on the third TFT and the fifth TFT under a control of a second scan signal, keeping the voltage at the gate of the driving TFT unchanged by the capacitor, and making the driving TFT continue to be turned on, and driving the OLED to emit light by a power supply voltage; and turning off the first TFT, the second TFT and the fourth TFT.
9. The method of claim 8, wherein the first TFT, the second TFT, the third TFT, the fourth TFT, and the fifth TFT and the driving TFT are all P type Thin Film Transistors, and the first electrode of the driving TFT is the drain of the driving TFT;
the power supply voltage terminal supplies a positive power supply voltage, the positive power supply voltage is higher than a reference voltage at the reference voltage terminal, and a data voltage of the data voltage signal is lower than the positive power supply voltage.
10. The method of claim 9, wherein, in the pixel circuit, an anode of the light-emitting element is connected to the drain of the third TFT, and a cathode of the light-emitting element is connected to the reference voltage terminal.
US14/132,614 2012-12-21 2013-12-18 Pixel circuit, driving method thereof, and display device Active 2034-12-19 US9483979B2 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CN2012105647428A CN103000134A (en) 2012-12-21 2012-12-21 Pixel circuit, driving method of pixel circuit and display device
CN201210564742.8 2012-12-21
CN201210564742 2012-12-21

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10535306B2 (en) 2016-08-12 2020-01-14 Boe Technology Group Co., Ltd. Pixel circuit, display panel, display device and driving method
US10692430B2 (en) 2015-05-28 2020-06-23 Lg Display Co., Ltd. Organic light emitting diode display with threshold voltage compensation

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103198793B (en) * 2013-03-29 2015-04-29 京东方科技集团股份有限公司 Pixel circuit, drive method and display device thereof
CN103236238B (en) * 2013-04-26 2015-07-22 北京京东方光电科技有限公司 Pixel unit control circuit and display device
CN103258501B (en) * 2013-05-21 2015-02-25 京东方科技集团股份有限公司 Pixel circuit and driving method thereof
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CN104050919B (en) * 2014-06-18 2016-03-16 京东方科技集团股份有限公司 Image element circuit and display device
CN104167170B (en) 2014-07-10 2016-08-31 京东方科技集团股份有限公司 Image element circuit and driving method thereof and display device
CN104282263A (en) * 2014-09-25 2015-01-14 京东方科技集团股份有限公司 Pixel circuit, drive method thereof, display panel and display device
CN105448235B (en) 2014-09-28 2018-01-26 昆山工研院新型平板显示技术中心有限公司 AMOLED pixel cells and its driving method, AMOLED display device
CN104318897B (en) * 2014-11-13 2017-06-06 合肥鑫晟光电科技有限公司 A kind of image element circuit, organic EL display panel and display device
CN105528997B (en) * 2016-02-04 2018-09-21 上海天马有机发光显示技术有限公司 A kind of pixel circuit, driving method and display panel
CN105679236B (en) 2016-04-06 2018-11-30 京东方科技集团股份有限公司 Pixel circuit and its driving method, array substrate, display panel and display device
CN107731156B (en) * 2016-08-12 2020-02-21 京东方科技集团股份有限公司 Compensation pixel circuit, display panel, display device, compensation and driving method
CN106448557B (en) 2016-12-26 2019-05-03 深圳市华星光电技术有限公司 Light emission drive circuit and organic light emitting display
CN109559686A (en) * 2019-01-18 2019-04-02 京东方科技集团股份有限公司 Pixel circuit, driving method, electroluminescence display panel and display device

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120147060A1 (en) 2010-12-10 2012-06-14 Jin-Tae Jeong Pixel, display device including the same, and driving method thereof
US8378930B2 (en) * 2004-05-28 2013-02-19 Sony Corporation Pixel circuit and display device having symmetric pixel circuits and shared voltage lines
CN202976780U (en) 2012-12-21 2013-06-05 北京京东方光电科技有限公司 Pixel circuit and display device
US9111486B2 (en) * 2010-05-10 2015-08-18 Samsung Display Co., Ltd. Organic light emitting display device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101165474B1 (en) * 2005-12-29 2012-07-18 엘지디스플레이 주식회사 Pixel Circuit in Organic Electro-Luminescence Display Device
CN102708790A (en) * 2011-12-01 2012-10-03 京东方科技集团股份有限公司 Pixel unit driving circuit and method, pixel unit and display device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8378930B2 (en) * 2004-05-28 2013-02-19 Sony Corporation Pixel circuit and display device having symmetric pixel circuits and shared voltage lines
US9111486B2 (en) * 2010-05-10 2015-08-18 Samsung Display Co., Ltd. Organic light emitting display device
US20120147060A1 (en) 2010-12-10 2012-06-14 Jin-Tae Jeong Pixel, display device including the same, and driving method thereof
CN102568374A (en) 2010-12-10 2012-07-11 三星移动显示器株式会社 Pixel, display device including the same, and driving method thereof
CN202976780U (en) 2012-12-21 2013-06-05 北京京东方光电科技有限公司 Pixel circuit and display device

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Chinese Rejection Decision Appln. No. 201210564742.8; Issued Aug. 6, 2014.
First Chinese Office Action dated May 23, 2014; Appln. No. 201210564742.8.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10692430B2 (en) 2015-05-28 2020-06-23 Lg Display Co., Ltd. Organic light emitting diode display with threshold voltage compensation
US10535306B2 (en) 2016-08-12 2020-01-14 Boe Technology Group Co., Ltd. Pixel circuit, display panel, display device and driving method

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